The use of ceiling boards, or tile, is well known. Such boards can be made of any suitable material. Those containing glass fibers and having a surface coating find wide usage. Frequently, such boards are supported on gridwork. Certain boards so supported drop slightly below the gridwork so that the edge retained on the gridwork, which edge is thinner than the board proper, is exposed.
In order to provide a finished appearance to such edges, it has been customary to apply an edge coating. However, such coatings frequently are susceptible to voids and cracking and tend to "wick" into, or be absorbed by, the basic material of the board. To prevent this, multiple pass coating has been resorted to in addition to, in some instances, oven drying.
The ceiling board edge coatings of this invention avoid such difficulties and do not require oven drying or special application procedures.